Time locking control apparatus for railways



April 17, 1956 A. HOOGERHYDE TIME LOCKING CONTROL APPARATUS FOR RAILWAYSFiled Nov. 50, 1951 2 Sheets-Sheet l April 17, 1956 HQOGERHYDE TIMELOCKING CONTROL APPARATUS FOR RAILWAYS Filed Nov. 30, 1951 2Sheets-Sheet 2 g Q m E W w A ER W n W w W. A a A m w S m w m m m w m R a0% m K mm M Q UT m wwww w W w m "HT m u g m M wfi m m EM 11,----l--i:l WSB 1? i LP RN 1F 4 w NI for railways.

2,742,563 I tented Apr. 17, 1956 TIME LOCKING CONTROL APPARATUS FORRAILWAYS Arthur Hoogerhyde, Verona, Pa.', assignor to Westing house AirBrake Company,Wilmerding, Pa., a corporation'of Pennsylvania ApplicationNovember 30, 1951, Serial No. 259,045 13 Claims. (Cl. 246-160) Myinvention relates to time looking control apparatus More specifically,my invention relates to a releasing arrangementfor time lockingcontrolapparatusfor railways such, for example, as approach lookingapparatus for railway traffic governing devices which may be trackswitches in an interlocking'plant.

This application is a continuation in-part of my earlier A l a homesignal is controlled to display a stop indication,

if a train has arrived adjacent the signal before the signal iscontrolled to display the stop indication. I

I shall describe two forms of apparatus embodying my invention,-andshall then point out the novel features thereof in claims. 1

l'n the accompanying drawings, Fig. 1 is a diagraminatic view'showingone form of apparatus embodying my invention, in which the stretch oftrack between a V home'signal Zand its approach signal 2D is dividedinto application for Letters Patent of the United States, Serial No.239,446, now abandoned,'filed July 31, 1951, for Time Locking ControlApparatus for Railways. Fig. 1 of the present application corresponds toFig.1 ofithe earlier application, and Fig. 2 of the present applicationI is a modification of Fig. 2 of the earlier application.

When setting the operating time of releasesfor approach locking,railroads generally make use of a standard formula given in Part 128 ofThe Association of American Railroads Signal Section Instructions. Asdetermined by that formula, the length of the releasing time dependslargely on the distance between a home signal and an approach signal forthe home signal which controls traflic movements over a switch orother't'rafiic governing device to which the approach locking isapplied,

so that, ifthe distance is long between the home signal v the releasingtime Types of traffic movements'which may result in hnnecessarily longdelays to trains are as follows: (l)i If a train approaches a homesignal which has been controlled to display a proceed indication for athrough traffic movement on a main track, but the engineman of the trainwishes to make a movement onto an auxiliary track to leave a bad ordercar such, for example, as a car with a hot box. (2) If a train moves offof an interlocking track layout or siding area, and a leverman controlsa home signal to display a proceed indication for the train to reenterthe interlocking trackklayout or siding area by a route other than thatwhich is desired by the engineman on the train.

With either of these two types of traffic movements, the home signalwill be controlled to display a stopindication after having first beencontrolled to display 'a proceed indication; operation of the timereleasing means for the approach locking will be thereby initiated; uponexpiration of the release time period, the switches for,

the desired route can be moved to the positions in-which they areincluded in that route; and the home signal can then be controlled todisplay a proceed indication for the desired route. With timereleasing-arrangements :previously used, a long release period would beimposed in the event of either of the two types of trafiic movementsreferred to, even if the train had stopped before two approachsections designated by the reference characters AT and ET; in which twotime element devices or relays which may be of the well-known thermaltype, designated by the reference characters TER and ATER, are provided;in which two approach locking relays designated by the referencecharacters 2LSR an d A2LSR are provided; and in which the approachcontrol of relay ZLSR is inresponse to occupancy of an approach sectionCT inthe'rear of signal 2]) and in response to-occupancy of section BT,whereas the approach control of relay AZLSR is in response to occupancyof section AT only.

Fig. 2 is a diagrammatic view showing a modification of the apparatus ofFig. 1, also embodying my invention, in which only one approach lockingrelay ZLSR is provided; in which an approach relay, designated by thereference character 2AR,'is of the polarized type, and is controlled to'be energized by current of reverse polarity when any one of theapproach sect-ions AT, BT and CT is occupied by a train; and in whichthe approach control of relay ZLSR is effected by-relay 2AR in responseto occupancy of any one of the'three'section s'AT, BT and Similarreference characters refer to similar parts in each of the views} wIn'each of the Figures 1 and 2 of the drawings, a stretch of railwaytrack is shown including a track switch, designatedby the referencecharacter 3.- In order to simpljfy 'the drawings, each track, comprisingtwo parallel series of track rails, is represented by a single line.

The stretch of trackis divided by insulated joints 1 to form a detectortrack section, designated by the reference character 3T, in which switch3 is located, and a first and asecond and alsoI-a third approach sectiondesignated by the reference characters CT, BT and AT, respectively. Eachof the track sections is provided with a track circuit includingasuitable sourceof current such, for example, as a batteryf4, connectedacross the rails adjacent'one' end of the section, and a track relay,designated bythe reference character R preceded by the referencecharacter for the corresponding section, connected across the railsadjacent the oppositeend of the section.

A home signal 2 isshown for governing traflic movements over section 3T,past switch 3, in a given direction from right to left, as shown in thedrawings, which I shall assume is the westbound direction. An approachsignal, designatedby the reference character 2D, is shown,

in the rear of section 'BT and in advance of section CT,

for governing trafiicmovements over sections BT and AT 3 in thewestbound direction, toward signal 2. Signals 2 and 2D may be of anysuitable design such, for example, as the well-known scarchlight type.

Switch 3 is operable between a normal extreme position, in which it isshown in the drawings, anda reverse extreme position, by suitablemechanism, designated by the reference character 3M. Energization ofmechanism 3M for moving switch 3 between its two extreme positions iscontrolled by a switch locking relay, designated by the referencecharacter 3LR, and by a manually operable switch control device such,for example, as a lever, designated by the reference character 3V.

Signal 2 is provided with a suitable mechanism, designated by thereference character 2G, which ,is operable from a normal or deenergizedposition to an approach proceed position or to a clear proceed position.While mechanism 2G is deenergized, signal 2 displays a stop indication,and when mechanism 26 is moved to the approach or clear proceedposition, signal 2 displays an approach proceed indication or a clearproceedindication,

respectively. Energization of mechanism 2G is controlled by a manuallyoperable signal control device s1 1ch,.for example, as a lever,designated by the reference character 2V. Selection between the approachand the clear proceed position is effected by suitable means not part ofmy invention, and therefore not shown in the drawings.

Each of the levers 2V and 3V has a normal position, designated by thereference character 11, in which it is shown in the drawings, and acontrol position, designated by the reference character 1'. Lever 2V hasalso a second control position designated by the reference character f.Contacts operated by levers 2V and 3V are represented on the drawings bycircles, in which are placed reference characters to show the positionsof the respective levers in which the contacts are closed. Contact oflever 2V, for example, shown in the lower left-hand corner of each ofthe drawings, is closed only while lever 3V is in the n position, asindicated by the reference character n in the circle for this contact.Contact 34 of lever 2V, in Fig, 2, as another example, is closed onlywhile lever 2V is in the n or the r position or at any point betweenthesepositions, as indicated by the reference character nr in the circlefor this contact.

Signal contacts, designated by the reference characters g and y, areoperated in conjunction with signal mechr anism 2G, and are normallyclosed, while mechanism 2G is in the deenergized position, but arearranged so that contact g will be opened when mechanism 2G is moved tothe clear proceed position, and contact y will be opened when mechanism26 is moved to the approach proceed position. 1

A signal indication relay, designated bythe reference character 2RP, iscontrolled by contacts g and y, so that it is normally energized whilemechanism 2G is inthe deenergized or stop position, but becomesdeenergized when mechanism 2G is moved to either of its proceedpositions.

A suitable source of current may, for example, be a battery, shown inthe drawings and designated by the reference character Q, havingterminals designated by the reference characters B and N.

Referring to Fig. 1 of the drawings, an approach relay, designated bythe reference character 2AR, is here controlled by front contacts ofrelays BTR and CTR.

A first and a second approach locking relay, designated by the referencecharacters 2LSR and A2LSR,respeetively, are shown in Fig. 1.

A first and a second time element device or relay which may. be of thewell-known thermal type, designated by the reference charactersTER andATER, respectively, are also shown in Fig. 1. Each of the devices TERand ATER is provided with a back contact 46 or 50, respectively,

which is normally closed, while the correspondingdevicc is deenergized,but becomes opened when the corresponding device becomes energizedand-isthen slow 'to close when the corresponding device becomes deenergized.

'Each of the devices TER and ATER is also provided with a front contactor 49, respectively, which is normally open, but which becomes closedupon the lapse of a corresponding measured period of time after thecorresponding device becomes energized. First and second timing stickrelays are also shown, designated by the reference characters TESR andATESR, respectively.-

I shall assume that the time setting of the TER-TESR relay combinationis that which is required for a distance equal to the sum of the lengthsof the track sections CT and ET. I shall also assume that the timesetting of the ATER-ATESR relay combination is that which is requiredfor-a distance equal to the length of track sectibmAT, which is shorterthan the sum of the lengths of sections CT and BT.

Each of the approach locking relays 2LSR and A2LSR has pickup and stickcircuits which include a front contact of relay ZRP and an nr contact oflever 2V. An energizing circuit for each of the time element devices orrelays TER and ATER also includes a front contact of relay 2RP and an nrcontact of lever 2V. The energizing circuit for time element device orrelay TER includes back contacts of relays 2LSR and TESR, and anenergizing circuit for time element device or relay ATER likewiseincludes back contacts of relays A2LSR and ATESR. As shown in Fig. 1,relay 3LR is energized only while relay 3TR and approach locking relays2LSR and A2LSR are all energized.

Referring now to Fig. 2 of the drawings, a slow release signal controlrelay, designated by the reference character ZDHR, for signal 2D, iscontrolled by front contacts of relays ATR and BTR. A slow releasedirectional stick relay, designated by the reference character 2DSR, iscontrolled by relays BTR and ZDHR. A second slow release directionalstick relay, designated by the reference character ESR, is controlled byrelays 3TR and ATR to become energized when a train moves from section3T onto section AT.

Approach relay ZAR is here of the polarized type, energized by currentof normal polarity while the three approach track sections areunoccupied, but controlled to become energized by current of reversepolarity when any one of the approach sections CT, BT and AT becomesoccupied by a westbound train. A repeater relay, designated by thereference character APR, is controlled by a front contact of relay ZAR,and is of a slow releasing type, so that it will retain its frontcontacts closed during the intervals between energization of relay 2ARby current of normal polarity and energization of relay ZAR by currentof reverse polarity.

Only one approach locking relay, designated by the reference characterZLSR, is required in the arrangement shown in Fig. 2. One of the pickupcircuits for relay 2LSR includes a normal polar contact 36 of relay 2ARin addition to a front neutral contact 37 of relay 2AR. A first timeelement relay TER, in Fig. 2, is controlled by a reverse polar contactof relay ZAR and by a from point of a contact 56 of relay APR. Relay TERmay also at times be controlled, through the back point of contact 56 ofrelay APR, over a portion of the energizing circuits for a second timeelement device or relay ATER. Relay SLR is here controlled by onlyrelays 3TR and 2LSR.

I shall assume that the time setting of relay TER, in Fig. 2, is thatwhich is required for a distance equal to the sum of the lengths oftrack sections CT and BT, and that the time setting for relay ATER isthat which is required for a distance equal to the length of tracksection AT, which is shorter than the sum of the lengths of sections CTand BT.

Having described, in general, the arrangement and con trol of thevarious parts of apparatus embodying my invention, I shall now describethe circuits and operation in detail.

As shown in the drawings, all parts of the apparatus are in the normalcondition, that is, all track sectionsare vand 37 ofrelay 2AR.

unoccupied, 'and therefore all track relays are energized; switch 3 isin its normal position; signal mechanism 2G is deenergized,and-is'therefore in the stop position; signal 2D is displaying anapproach proceed indication; each of the levers 2V and 3V is in its nposition; relays 2AR, 2LSR,'A2LSR, 3LR and 2RP in Fig. l are energized;relay 2AR in Fig. 2 is energized by current of normal polarity;mechanism 2DGis energizedfor controlling signal 2D to display an advanceproceed indication; relays 2DHR, 2LSR, APR, 3LR and 2RP in Fig. 2 areenergized; relays TER, TESR, ATER and ATESR in Fig. 1 are deenergized;and relays ESR, 2DSR, TER and ATER in Fig. 2 are deenergized.

As shown in each of the-Figures 1 and 2, relay 2RP is energized by acircuit passing from terminal B of battery Q, through'contact's g and yof signal 2, and the winding of relay 2RP to terminal N of battery Q.

As shown in Fig. l, relay 2AR is energized by a circuit passing fromterminal B, through contacts 5 and 6 of relays CTR and BTR,respectively, and the winding of relay 2AR to terminal N.

-Relay2LSR in Fig. 1 is energized by a stick circuit and by a firstpickup circuit. The first pickup circuit passes from terminal B, throughcontact 7 of lever 2V, contact 8 of relay 2RP, contact.9 of relay 2AR,and the winding of relay 2LSR to terminal N. The stick circuit for relay2LSR is the same as the pickup circuit just traced except thatit'includes the front point of contact 10 of relay 2LSR instead ofcontact 9 of relay 2AR.

. Relay AZLSR in Fig. 1 is also energized by a stick circuit and a firstpickup circuit. The first pickup circuit for relay A2LSR passes fromterminal B, through contact 11- of lever 2V, contact 12 of relay 2RP,,contact 13 of relay 2LSR, contact 14 of relay ATR, and the winding ofrelay AZLSR to terminal N. The stick circuit for relay AZLSR ,is thesame as the pickup circuit just traced except that it includes the frontpoint of contact 15 of relay.A2LSR instead of contact 14 of relay ATR.

Relay 3LR in Fig. 1 is energized by a circuit passing from terminal B,through contacts 16, 17 and 18 of relays 3TR, 2LSR, and A2LSR,respectively, and the winding of relay 3LRto,terminal N. Contact 19 ofrelay .3LR and contacts 20 and 21 of lever 3V are closed in a normaloperating circuit for switch mechanism 3M for switch 3. As shown in Fig.2, relay 2DHR is energized by a circuit passing from terminal B, throughcontacts 24 and 25 of relays ATR and BTR, respectively, and the winding.of relay 2DHR to terminal N. With relay 2DHR energized, mechanism 2DGfor signal 2D is energized by a circuit passing from terminal B; throughcontact 26 of relay 2DHR, and mechanism ZDG to terminal N.

Relay 2AR in Fig. 2 is energized by current of normal polarity passingfrom terminal B, through-the front points of contacts 27 and 28 ofrelays CTR and 2DHR, respectively, the winding of relay 2AR, and thefront points of contacts 29 and 30 of relays 2DHR and CTR, respectively,

, vto terminal N. With relay 2AR energized, relay APR is energized by acircuit passing from terminal B, through contact 33 of relay 2AR, andthe winding of relay APR to terminal N.

Relay 2LSR in Fig. 2 is energized by both a stick circuit of relay 2AR,and the winding of relay 2LSR to terminal .N. The stick circuit forrelay 2LSR is the same as the fpickup circuit just traced except that itincludes the front point of contact 38 of relay 2LSR instead of contacts36 7 Relay 3LR is here energized by a circuit passing from terminal B,through contacts 39 and 40 of relays 3TR and 2LSR, respectively, and thewinding of relay 3LR to terminal N. Contact 19 of relay 3LR and contacts20 ll'l d: 21 of lower 3V'are here closed in a normal operatingcircuitfor switch mechanism 3M, as in Fig. 1.

I shall assume that, with the apparatus arranged as shown in Fig. l, aleverman or dispatcher moves'lever 2V to its f position to clear signal2 for a westbound train to move past switch 3. Signal mechanism 26 willtherefore be energized by a circuit passing from terminal B, throughcontact 41 of lever 2V, and mechanism 2G to terminal N, for controllingsignal 2 to display an approach proceed or a clear. proceed indicationas selected by means not shown in the drawings.

Lever 2V, upon being moved away from its 11 position toward the 1position, opens its contacts 7 and 11, there- 1 by deenergizing relays2LSR and AZLSR.

With signal 2 displaying either an approach or a clear proceedindication, contact y or contact g of this signal will be open, andtherefore relay 2RP will bedeenergized.

With relays 2LSR and A2LSR deenergized, contacts 17 and 18,respectively, of these relays will be open, and therefore relay 3LR willbe deenergized. With relay 3LR deenergized, contact 19 will be open inthe operating circuits for switch mechanism 3M, and therefore mechanism3M could not now be energized for moving switch 3 to the reverseposition.

I shall assume further that a westbound train enters section CT, therebydeenergizing relay CTR, which, in turn, at its contact 5, opens thecircuit for relay 2AR, causing relay 2AR to be deenergized. When thetrain enters section ET, the circuit for relay 2AR will be opened atanother point by contact 6 of relay BTR. When the train enters sectionAT, relay ATR will be deenergized, and therefore its contact 14 will beopened in the pickup circuit previously traced for relay A2LSR, whichis, however, already deenergized on account of the opening of contact 11of lever 2V. When the train enters section 3T, relay 3TR will becomedeenergized, and therefore its contact 16 will open the circuit forrelay3LR at a third point. If, now, while the train is on section 3T, aleverman or dispatcher returns lever 2V to its n position, contact 41 oflever 2V will open the circuit previously'traced for signal mechanism26, causing mechanism 2G to be deenergized and relay 2R1 to in turnagain becomeenergized by its circuit previously traced. A second pickupcircuit will now be completed for energizing relay 2LSR, this circuitpassing from terminal B, through contact 7 of lever 2V, contact 8 ofrelay 2RP, contact 42 of relay 3TR, and the winding of relay 2LSR toterminal N. With relay 2LSR energized, a second pickup circuit will alsobe completed for relay A2LSR, this. circuit passing from terminal B,through contact 11 of lever 2V, contact again in the normal condition,and that, again, a leverman or dispatcher moves lever 2V to its fposition for clearing signal 2. I shall vassume further that a westboundtrain enters section CT, and that while the train is moving over sectionCT or section ET, the leverman or dispatoher returns lever 2V to its 11position, thereby controlling signal 2 to again display the stopindication, and causing relay ZRP to again become energized.

With the train on section CT or, BT, relay 2AR will be deenergized, andtherefore its contact 9 will be open in the first pickup circuit tracedfor relay 2LSR. Relay 2LSR will therefore remain deenergized when lever2V is returned to its n position, and an energizing circuit will becompleted for time element device or relayTER, this circuit passing fromterminal B, through contact 7 of lever 2V, contact 8 of relay 2RP, backpoint of contact 10 of relay 2LSR, the back point of contact 44 of relayTESR, and the control element of d'eviceTER to terminal N. Device TERwill then open its contact 46 and, upon the lapse of a measured periodof time, will close its contact 45, thereby completing a pickup circuitfor ,relay,.TESR,, this circuit passing from terminal B, through contact45 ofrelay TER, and the winding of relay TESR to terminal N. Relay TESR,upon becoming energized, will complete its own stick circuit, which isthe same as the energizing circuit previously traced for relay TERexcept that it includes the from point of contact 44 of relay TESRinstead of the back point of this contact.

Relay TESR,UPO11 opening its contact 44, at the back point, deenergizesrelay TER, so that contact 46 of relay TER then again becomes closed,upon the lapse of a brief period of time. Another, or third, pickupcircuit will now be completed for relay ZLSR, this circuit passing fromterminal B, through contact 7 of lever 2V, contact 8 of relay ZRP,contact 46 of relay TER, contact 4-7 of relay T ESR, and the winding ofrelay ZLSR to terminal N. Relay 2LSR, upon becoming energized, opens itscontact 10 at the back point, thereby deenergizing relay TESR.

1f the westbound train should stop on section CT or section BT, or if itshould move so slowly that energization of relay ZLSR by its thirdpickup circuit would be effected by relay T ER before the train enterssection AT,-relay AZLSR would become energized by its first pickupcircuit, previously traced, as soon as relay 2LSR closed its contact 13.Relay SLR would therefore become energized upon the lapse of only theperiod of time determined by relay TER.

It follows that, in this event, the approach locking of relay .3LR isreleased after only a short period of time, determined by relay TER,instead of after a long period of time as determined by the operatingtime of both relays TER and ATER.

If, however, the train enters section AT before relay AZLSR has becomeeenergized, contact 14 of relay ATR would be open in the pickup circuitfirst traced for relay A2LSR, and therefore relay AZLSR would not becomeenergized as soon as relay ZLSR becomes energized.

When relay 2LSR closes its contact 13, an energizing circuit would,however, be completed for time element relay ATER, this circuit passingfrom terminal B, through contact 11 of lever 2V, contact 12 of relay2RP, contact 13 of relay ZLSR, back point of contact 15 of relay A2LSR,backpoint of contact 48 of relay ATESR, and the winding of relay ATER toterminal N. Relay ATER would then open its contact 50 and, upon thelapse of a measured period of time determined by relay ATER,

contact 49 of relay ATER would become closed and thereby complete apickup circuit for relay ATESR, this circuit passing from terminal B,through contact 49-of relay AT ER, and the winding of relay ATESR toterminal N. Relay ATESR, uponbecoming energized, would complete its ownstick circuit, which is the same as the I contact 11 of lever 2V,contact 12 of relay ZRP, contact 13 of relay ZLSR, contacts 50 and 51 ofrelays ATER and ATESR, respectively, and the winding of relay AZLSR toterminal N. Relay AZLSR, upon becoming energized,

will open its contactlS at theback point, thereby deenergizing relayATESR. Relay AZLSR will also complete its own stick circuit previouslytraced through the front point of its contact 15,

The approach locking of relay 3LR by relays ZLSR andAZLSR is nowreleased after a time interval deter- 8 mined'by both relays TER' andATERg This releasing time is therefore longer than the release timedetermined in the previous example given, in which relay ZLSR becameenergized before the train entered section AT.

I shall next assume that, with all parts of the apparatus again in thenormal condition, the leverman or dispatcher again moves lever 2V to itsf position for energizing mechanism 2G tocontrol signal 2 to againdisplay a proceed indication.

I shall assume further that a westbound train proceeds over sections CTand BT, and stops on section AT because the engineman desires to moveover switch 3 in its reverse position instead of in the normal position.The leverman or dispatcher will then return lever 2V to its n position,causing signal mechanism 26 to returnto the stop position .and therebycausing relay 2RP to in turn again become energized.

With sections CT and BT unoccupied, relay 2AR will be energized by itscircuit previously traced. Relay 2LSR will therefore become energized atonce by its pickup circuit first traced, when lever 2V is returned toits n position. Relay ATER will now become energized by its circuitpreviously traced, and, upon the lapse of a measured period oftime,relay ATESR will become energized. Relay A2LSR will therefore becomeenergized by its third pickup circuit, previously traced, upon the lapseof only the period of time determined by relay ATER, which is shorterthan the time required when the leverman returned signal 2 to stop whilea train was moving rapidlyover section CT and BT so that the trainentered section AT before relay AZLSR became energized.

I shall now assume that, instead of a westbound train moving oversections CT and BT, an eastbound train is to move over switch 3 in itsreverse position. A leverman or dispatcher will therefore effectoperation of switch 3 to its reverse position by moving lever 3V to itsr position, thereby completing a reverse operating circuit for mechanism3M, passing from terminal B, through contact 19 of relay 3LR, contact 23of lever 3V, mechanism 3M, and contact 2201 lever 3V to terminal N.

I shall assume further that the train, upon moving over switch 3 in itsreverse position, stops on section AT, preparatory to reversing itsmovement. I shall assume still further that the leverman controls signal2 to display a proceed indication for the train to move back over switch3 in the reverse position, whereas the engineman desires to go overswitch 3 in its normal position. It is therefore necessary for theleverman to now return lever 2V to the 11 position. With sections CT andBT unoccupied, relay 2AR will be energized, as previously described. andtherefore relay ZLSR will now become energized without the delaytimeimposed by relay TER. The approach locking will therefore be releasedupon the lapse of only the time determined by relay ATER, as previouslydescribed for a westbound train which had stopped on section AT.

It follows that, with apparatus arranged as shown in Fig. 1, myinvention provides means for releasing aproach locking in a short timeif a leverman or dispatcher changes the indication of a home signal froma proceed indication to a stop indication after a train has arrivedadjacent signal 2 and stopped on the approach section AT, whereas, ifthe leverman or dispatcher changes the indication of a home signal fromproceed to stop whilea train is approaching at high speed at a longerdistance away, a longer time, determined by both relays TER and ATER,will be required for the release of the approach locking.

I shall assume that, with apparatus arranged as shown in Fig. 2, aleverman or dispatcher moves lever 2V to the position. Mechanism 26 willthen be operated, and relay 2R1 will become deenergized, as previouslydescribed in connection with Fig. 1. Contact 34 of lever 2V will openthe stick andfirst pickup circuits for relay senses when levenzV ismoved away from its ftp'o'sition towarditsf position, and thereforerelay 2LSR will be 'deenergized, and, in turn, relayf3LR will bedeen'ergized, becausef the opening of contact 40 of relay ZLSR. Withrelay 3LR deene'rgized, its contact 19 will be open in 'e operating 3circuits for switch mechanism 3M, and

therefore switch 3 cannot be'moved. v "I shall assume further that awestbound train new enterssection CT. Relay 2AR,wi1l therefore beenergized by current of reverse polarity in a circuit which is the same"as the circuit traced for energizing this relay by'current of normalpolarity except that it includes the back points of contacts 27 and 30of-rel'ay CTR instead of the front points jof-these'contacts. With relayZAR energized by current of reverse polarity, its contact 36 will beopen in the pickup circuit first traced for relay ZLSR. Relay APR will,however, remain energized by its circuit previously traced. With relay2AR energized by current 'of reverse polarity, and with relay APRenergized,

relayTER becomes energized as soon as the westbound train 'enterssectionCT, althoughlever 2V is still in its 1 position. Operation of relay TERis therefore started for closing its contact 57 upon the lapse of ameasured period of time.

i QWhen-"the westbound train enters section BT, 'contact 25'of relay BTRwill open the circuit for relay ZDHR which is slow releasing'and whichwill therefore not open same as thelpickup circuit just traced except.that it includes contact 54 of relay ZDSR instead of the front point ofcontact 53 of'relay ZDHR. Upon the lapse of a brief period of time, thecontacts of relay 2DHR will bercleased, and therefore a second stickcircuit will be completed forrelay 2DSR,-this circuit passing fromtermian ['13, through-the back point of contact 53 of relay 2DHR,contact 54 of relay ZDSR, and thewinding of relayv ZD SR to terminal N;

With relay 2DSR energized and'relay ZDHR deenergized, asecond circuit isnow completed for energizing relay ZAR bycurrent of 'reverse polarity,this circuit passing from terminal B, through contact 31 ofrelay 'ZDSR,back point of contact29 of relay ZDHR, winding of relay ZAR, back pointof contact 28 of relay ZDHR, andcontact32 ofirelay ZDSR to terminalSince relay ZDHR is controlled by relays. ATR and BTR,'it follows thatrelay ZAR will remain energized by current of reverse polarity as longas the train remains on any, portion of sections, BT and AT, as well aswhile the train isj on section CT.

I shall now assume still further'that, while the train is on one of thesections CT BT or AT, a leverman or dispatcher returns lever 2V to its11 position. .Mechanism 2G will then be returned to the stop position,and relay 2R1 will again be energized, as previously described.

1 As soon ,as the westbound train enteredsection CT,

causing relay 2AR to become energized by current of reverse polarity,relay .TER became energized by' a circuit passing from terminal B,through contact 55 of relay 2AR, front point of contact 56v of relayAPR, and the winding of relay TER to terminal N. The operation of relayTER therefore began at thetime the train entered section CT, instead ofnot until lever 2V was returned to its n position, as with the apparatusarranged as in Fig. 1. Upon the lapse of the remaining portion of themeasured period of time for operating relay TER, after lever 2V tact 57,thereby completing an energizing circuit for relay lever"2V contact 35of relay ZRP, back point of can:

tact 38 of relay 2LSR,'contact 57 of'relay TER, and the winding of relayATER to terminal N.

With relay ATER energized, another, or third,pick'+ up circuit will becompleted for relay ZLSR, upon the lapse of a further measured periodoftime, this circuit passing from terminal B, through contract 34 oflever 2V, contact 35 of relay ZRP, contact 59 of relay ATER, and thewinding of relay 2LSR to terminal N. 'Th approach locking of relay SLR,as effected by relay 2LSR', will therefore be released upon the lapse ofa measured period of time as determined by relay ATER 'and the portionof the time remaining for the operation of relay TER' atthe time theleverman returns lever 2V to the 12 position. 1 If the leverman ordispatcher does not return lever 2V to the n position until after thetrain h'asstopped adjacent signal 2, sufiicient time will have elapsedfor relay TER to have closed its front contact 57, and therefore relayATER'will become energized'at once. The release of the approach lockingof relay 3LR, after lever 2V is thus returned to its n position, willthereforebe effected upon the lapse of a measured periodof timedependent upon only relay ATER, which is shorterth'an would be requiredif lever 2V were' returned to its 'ri position while' the train ismoving rapidly over section CT orfsection'fBTsothat the measured periodof time for relay TER to close its-contact 57 has ;not elapsedbefore'tlie return of lever 2V' t o its n pos'ition.

I shall now' -ass'urhe' that a,'l'ever'man or dispatcher reverses switch3, as previously described, for an eastbound train to] move from anauxiliary track onto the main tracln'When the eastbound train enterssection 3T; relay ESR' will become energized by a pickup circuit passingf romt'erminal B, 'through contact 61 of relay 3TR, front'point ofcontact'62 of relay ATR, and'the im'nding of'rel'ay ESR to terminal N.Relay ESR, upon becoming energized, will complete a stick circuit whichis the same as the pickup circuit-just traced except that it includescontact 63 of relay ESR instead of the front point of contact 62 ofrelay ATR. When the train enters section.-'AT-, causing the contacts ofrelayATR to become released, a secon d stick circuit will'be completedfor relay ESR, passing from terminal B, through the back pointof contact62of relay'ATR, contact63 of relay ESR, and the winding'of relay ESR= toterminal N. If'the leverman or dispatcher now clears signal-2 for thetrain to return over switch'3 reversed, whereas the en'gineman' desirestoumove over switch 3 normal, and if the leverman .then returns lever 2Vto its n position; relayATER' will'at once become energized by a'cincuit passing fr'omterm'inal'B, through contact 34;of le'ver ZVicontact35'ofrelay ZRP, .back point of contact 38 of reIay'ZLSR, contact 58 ofrelay ESR, and the winding of relay ATER to terminal N. It followsthat,funder these conditions, the release ofqthe, approach locking ofrelay 3LR Willibe efiecteduponthe lapse of only the period of timedetermined byrelay ATER instead of by both relays TER and ATER. I v

From the foregoing description of operation of apparatus arranged as inthe-modifiedform' shown in Fig. .2,

'ATER, after lever 2V is returned to the 11 position, before release.ofthe. approach ,locking can be. eifected ,-,If, however, .the levermandoes. not return lever 2V, ,'t:;t h n position until after relay TER hascompleted its operation and closed its contact 57, the approachlockingwill then be released upon the further lapseof only the time requiredfor relay ATER to be operated, for closing its contact 59. It is to beunderstood that the time of operation. of relay TER is selected so thatit will have expired by the time the train has left sectionB'L-Therefore, if the leverman returns lever 2V to the, n positionat anytime after the train has left section BT,-as .when it has stopped atsignal 2, the approachlocking will be released at the expiration of thetime required foropera tion of only relay ATER after the return of lever2V to its 11 position.

It follows that apparatus embodyingmy invention, eitheras shown inFig.1, or as in the modified form shown in Fig. 2, provides means forreleasing approach locking upon the lapse of a short period of time if aleverman or dispatcher returnsleverZV to the 11 position after a trainhas stopped at the home signal 2, but that a longer time is required forthe release of approach lockingif the leverman returns lever 2V to the)1 position soon after a westbound train, moving at high speed, entersthe approach zone which includes sections CT, BTand AT.

In the modified form of apparatus shown inFig. 2, a

second circuit is provided for energizingrelayTER,

through the baek point of contact 56 of relay APR, after a leverman ordispatcher has returned lever 2V to its n position, if relay 2DSR hasfailed to become energized when a westbound train entered section BT, or.if relay ESR has failed to become energized in response to-an eastboundtrain. Without this second circuit for energizing relay TER in the eventof such a failure of relay ZDSR or relay ESR to become energized, thetime element relays would remain deenergized until after the cause ofthe failure had been removed by a maintainer orother authorized person.In the meantime, approach locking relay ZLSR would remaindeenergized,,causing relay SLR to also remain deenergized, andtherefore, switch 3 would remain locked and cause anunnecessary traindelay.

In the event of failureofrelay 2DSR,.or relay ESR to become energized,there is no need for retaining thcswitch in the locked condition afterthe lapse of a period ,of time determined by both relays TER and ATER,.asinitiated, by the second energizing circuit for relay .TER throughthe back point of contact 56 of relay APR.

I shallassume that, as previously described,-with apparatus arranged asshownin Fig. -2, a leverman or. a dispatcher moves lever 2V to its 1position to .clearsignal 2 for a westbound train, thereby deenergizingrelay,.2LSR,

and that a westbound train then enters section CT, causing r.

relay 2AR to become energized by' current of-reverse polarity. I Withrelay 2AR energized by current of reverse polarity, the first energizingcircuit for relay TER, previously traced through the front point ofcontact. 56:01?

relay APR, will be completed, and will start operation of t relay'TER.

When the train enters section BT, relay 2DH'R will become deenergized,thereby opening the circuit, previously described, including theback-points of-contacts27 and 30 of relay CTR, for energizing relay ZARby current of reverse polarity. I shall assume further -that relay ZDSRhas failed to become energized when the train entered section ET. Thesecond circuit, previouslytraced, including contacts 31 and 32 of relayZDSR, for energizing relay 2AR by current of reverse polarity, willtherefore i of relay ZRR, back point of contact 38 of relay 2I.;S R,baelr point of contact 56 of relay APR, and the winding of relay TER, toterminal N. Upon the lapse of a measured period of time as determined byrelay TER, relay ATER will become energized, and upon the lapse of afurther measured period of time as determined by relay ATER, relay 2LSRwill become energized by its third pickup circuit and will release thelocking of switch 3, as previously described. 7

I shall now assume that a train moves eastward off of the auxiliarytrack, over switch 3 reversed, and that relay ESR fails to becomeenergized. If a leverman or a dis patcher then clears signal 2 for thetrain to move westward, .and if he then again returns lever 2V to its 11position, relay ATER will not at once become energized as previouslydescribed, because contact 58 of relay ESR has not become closed.

With the train on section AT, ,relay ZDHR will be deenergized, andtherefore relay 2AR will in turn also be deenergized. Relay TER willtherefore become energized by, its second circuit, including the backpoint of contact 56 of relay APR, as previously described in connectionwith an assumed failure of relay ZDSR to become energized. As in case ofa failure of relay ZDSR, relay ZLSR will then become energized upon thelapse of a measured period of time determined by both relay TER andrelay ATER.

I have described the operation of the apparatus embody.- ing myinvention for a few typical trafiic movements, It is believed that inview of such description, taken with the accompanying drawings, theoperation of the apparatus for any other possible trafiic movement canbe readily traced without further detailed description.

Although I, have herein shown and described only two .forms of apparatusembodying my invention, it is under,- stood that various changes andmodifications may be made therein within the scope of the appendedclaims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Inapproach locking control apparatus for a stretch of railway trackwhich is provided with a traflic governing device and a home signal forgoverning trafficmovements in a given direetion past said trafiicgoverning device and also an approach signal in the rear of said homesignal for governing trafiic movements in said given direction towardsaid home signal, said stretch of track divided into a first approachsection in the rear of said approach signal and a second and a thirdapproach section between said approach signal and said home signal withsaid third approach section adjacent said home signal, the combinationcomprising, an approach locking relay, time element means, control meansmanually operable from a normal condition to a control condition forcontrolling said home signal to display a proceed indication, meanscontrolled by a train approaching said home signal. in said givendirection-and by said control means if said. control means is restoredto its normal condition while said train,is on said first approachsection for operating said time element means for energizing saidapproach locking relay ,upon the lapse ofa given measured period of timeafter said control means is restored to its normal condition, meanscontrolled by a train approaching said hometsignal in said givendirection and by; said control means if saidcontrol meansis restored toits normal condition while said train is on said third approach sectionfor operating ,saidtime element means for energizing said approachlocking relay upon the lapse of a second measuredperiod of time. whichis shorterthan said given measured period of tim,e, and means includinga contact of said approach lockingrelay for controlling said trafficgoverning device.

2. In approach locking control apparatus fora stretch of railway trackwhich is providedivith .a traffic governing device anda. home signal forgoverning traific movements in a given direction past said trat l'iegoverning device uid also an approach signalin the rear of saidhomesignal for l3 governing traific movements in said given directiontoward said home signal, said stretch of track divided into a firstapproach section in the rear of: said approach signal and a second and athird approach section between said approach signal and said home signalwith said third approach section adjacent said home signal, thecombination comprising, an approach locking relay, control meansmanually operable from a normal condition to a control condition forcontrolling said home signal to display a proceed indication, meanscontrolled by a train approaching said home signal in said givendirection and by said control means if said control means is restored toits normal condition while said train is on said first approach sectionfor energizing said approach locking relay upon the lapse of agivenmeasured period of time after said control means is restored to itsnormal condition, means controlled by a train approaching said homesignal in said given direction and by said control means if said controlmeans is restored to its normal condition while said train is onsaidthird approach section for energizing said approach locking relay uponthe lapse of a second measured period of time which is shorter than saidgiven measured period of time, and means including a contact controlledby said approach locking relay for controlling said trafiic governingdevice.

3. .In approach locking control apparatus for a stretch of railway trackwhich is provided with a signal for governing trafiic movements in agiven direction, said stretch of track divided into a first and a secondand also a third approach section arranged in the order named in therear of said signal with said third approach section adjacent saidsignal, the combination comprising, approach locking means, controlmeans manually operable from, a normal condition to a control conditionfor controlling said signal to display a proceed indication, meanscontrolled by a train approaching said signal in said given directionand by said control means if said control means is restored to itsnormal condition while said train is on said first or said secondapproach section for energizing said approach locking means upon thelapse of a given measured period of time after said control means is restored to its normal condition, means controlled by a train approachingsaid signal in said given direction and by said control means if saidcontrol means is restored to its normal condition while sa'id train ison said'third approach section for energizing said approach lockingmeans upon the lapse of a second measured period of time which isshorter than said given measured period of time, and traflic governingmeans controlled by means including said approach locking means in itsenergized condition.

4. In approach locking control apparatus for a stretch of railway trackwhich is provided. with a signal for governing traflic movements in agiven direction, said stretch of track divided into a first and a secondapproach section with said second approach section adjacent said signaland said first approach section in the rear of said second approachsection, the combination comprising, approach locking means, controlmeans manually operable from-a normal condition to a control conditionfor controlling said signal to display a proceed indication, meanscontrolled by a train approaching said signal in said given directionand by said control means if said control means is restored to itsnormal condition while said train is on said first approach section forenergizing said approach locking means upon the lapse of a givenmeasured period of time after said control means is restored to itsnormal condition, means controlled by a train approaching said signal insaid given direction and by said control means if said control means isrestored to its normal condition while said train is on said secondapproach section for energizing said approach locking means upon thelapse of a second measured period of time which isshorter than saidgiven measured period of time, and trafiic governing means conits'energized condition.

trolled byv means including said approach locking means in 5. Inapproach locking control apparatus for a stretch of railway track whichis provided with a signal for governing trafiic' movements in a givendirection, said stretch of trackdivided into a first and a secondapproach section with said second approach section adjacentsaid signaland said first approach section in the rear of said second approachsection, the combination comprising, approach locking means, controlmeans manually operable from a normal condition to acontrol conditionfor controlling said signal to display 9. proceed indication, meanscontrolled by a train approaching said signal in said given directionand by said control means if said control means is restored to itsnormal condition while said train is on said first approach section forenergizing said approach locking means upon the lapse of a givenmeasured. period of time after saidcontrol means is restored to itsnormal condition if .said train has not yet entered'said second approachsection,'means controlled by a train approaching said signal in saidgiven direction and by said control means if said control means isrestored to its normal condition while said train is on said firstapproach section for energizing said approach locking means upon thelapse of a second measured period of time which is longer than saidgiven measured period 'of time if said train enters said second approachsection before expiration of said given measured period of time,meanscontrolled by a train approaching said signal in said given directionand by said control means if said control means is restored to itsnormal condition while said train is on said second approach section'forenergizing said approach locking means upon the lapse of a thirdmeasured period of time which is shorter than said second measuredperiod of time, and 'trafiic governing means controlled by meansincluding said approach locking means in its energized condition.

6. In combination, a stretch of. railway track provided with a trafficgoverning device, a signal for governing trafiic movements in a givendirection past said tratfic governing device, a first and a secondsection of said track in the rear of said signalvwithsaid second sectionadjacent said signal and said first section in the rear of said secondsection, a first and a second approach locking relay, a first and asecond time element device, a control device manually operable from anormal position to a controlposition for controlling said signal todisplay a proceed indication, a first trafiic responsive device for saidfirst section normally energizedbut becoming deenergized in response toa train occupying said first section, a second trafiic responsive'devicefor said second section normally energized but becoming deenergized inresponse to a train occupying said second section, a first pickupcircuit and a stick circuit for said first approach locking relaycontrolled by said control device in its normal position and said firstpickup circuit also controlled by said first trafi'ic responsive devicein the energized condition, an energizing circuit for said first timeelement device controlled by said control device in its normal positionand by a back contact of said first approach locking relay, anotherpickup circuit for said first approach locking relay controlled by saidcontrol device in its normal position and by a contact controlled bysaid first time element device to become closed when said first timeelement device has been energized for a given measured period of time, afirst pickup circuit and a stick circuit for said second approachlocking relay controlled by a front contact of said first approachlocking relay and by said control device in its normal position and saidfirst pickup circuit for said second approach locking relay alsocontrolled by said second trafiic responsive device in the energizedcondition, an energizing circuit for said'second time element devicecontrolled by a front contact of said first approach locking'relay andby said controldevicein its normal position and also by a back contactof saidsecondapproachtlocking relay, another pickup circuit for saidsecond approach locking relay controlled by said control device in itsnormal position and by a contact closed in response to energization ofsaid second time element device a second given measured period of time,andmeans including front contacts of said first and second approachlocking relays for controlling said traffic governing device.

7. In combination, a railway track, a signal for governing trafiicmovements in a given direction on said track, a first and a secondportion of said track in the rear of said signal with said secondportion adjacent said signal and said first portion in the rear of saidsecond portion, a first traffic responsive device normally energized butbecoming deenergized in response to a train entering said first portion,a second traflic responsive device normally energized but becomingdeenergized in response to a train entering said second portion, a firstand a second approach locking relay, control means manually operablefrom a normal condition to a control condition for controlling saidsignal to display a proceed indication, a stick I circuit and a firstpickup circuit for siad first approach locking relay each controlled bymeans including said control means in its normal condition and saidfirst pickup circuit also controlled by said first trafiic responsivedevice in the energized condition, a stick circuit and a first pickupcircuit for said second approach locking relay each controlled by meansincluding a front contact of said first approach locking relay and saidfirst pickup circuit for said second approach locking relay alsocontrolled by said second' trafiic responsive device in the energizedcondition, a first and a second time element device energizedby meansincluding said first and second approach locking relays respectively inthe deenergized condition and said control means in the normal conditionand said second time element device also controlled by a front contactof said first approach locking relay, an-' other pickup circuit for eachof said first and second approach locking relays controlled by meansincluding said first and second time element device respectively in theenergized condition, and trafiic governing means controlled by meansincluding front contacts of said first and second approach lockingrelays.

8. In combination, a stretch of railway track provided with a trafiicgoverning device, a home signal for governing traffic movements in agiven direction on said' track past said traflic governing devicepanapproach signal in the rear of said home signal for governing trafficmovements in said given direction toward said home signal, a firstapproach section of; said tra'ckin' the rear of said approach signal, asecond and a third approach section of said track between said approachsignal and saidhome signal with saidthird approach section adjacent saidhome signal, a polarized approach relay normally energized by current ofnormal polarity but becoming e nergizedby current of reverse polarity inresponse to a train moving in said given direction over said approachsections, an approach locking'relay, afirst and'a second time elementdevice, means including a'reversepolar contact of said approach relayfor e'nergiziiigsaid first time element device, control means manuallyop'erable from a normal condition to a controlcoridition'fo-rcontrolling'said home signal'to display a proceed indication, a stickcircuit and a first pickup circuit for said approach locking relaycontrolled'by means including said control means in the normal conditionand said first pickup circuit also controlled by means including anormal polar contact of said polarized approach relay, an energizingcircuit for said second time element device controlled by meansincluding said control means in its normal condition and a back contactof said approach'locking relay and also'said first time element devicein the energized condition, another pickup circuit for saidapproachlocking relay controlled by means including said second time elementdevice in the'energized condition, and'rneans including a front contactof said approach locking relay for controlling said trafiic governingdevice.

9. In combination, a railway track, a signal for governing traflicmovements in a given direction on said track, an approach portion ofsaid track in the rear of said signal, a polarized approach relaynormally energized by'current of normal polarity but becoming energizedby current of reverse polarity in response to a train moving over saidapproach portion of said track, a first and a second time elementdevice, means including a reverse polar contact of said approach relayfor energizing said first time element device, control means manuallyoperable from a normal condition to a control condition for controllingsaid signal to display a proceed indication, an approach locking relay,a stick circuit and a first pickup circuit for said approach lockingrelay controlled by means including said control means in the normalcondition and said first pickup circuit also controlled bymeansincluding a normal polar contact of, said approach relay, energizingmeans for said second time element device controlled by means includingsaid control means in its normal condition and a back contact of saidapproach locking relay and also said first time element device in theenergized condition, another pickup circuit for said approach lockingrelay controlled by means including said second time element device inthe energized condition, and tratfic governing means controlled by meansincluding a front contact of said ap proach locking, relay.

10. In combination, a stretch of railway track provided with a trafiicgoverning device, a signal for gov erning trafficmovement in a givendirection past said trafiic governing device, a first and a secondportion of said track in the rear of said signal with said secondportion adjacent said signal and said first portion in the rear of saidsecond portion, a first and a second approa'ch locking relay, a firstand a second time element device, a control device manually operablefrom a normal position to a control position for controlling said signalto display a proceed indication, a first traflic responsive device forsaid first portion of said track normally energized but becomingdeenergized in response to a train occupying said first portion, asecond traffic responsive device for said second portion of said tracknormally energized but becoming deenergized in response to'a trainoccupying said second portion, a first pickup circuit and a stickcircuit for said first approach locking relay controlled by meansincluding said control device in its normal position and said firstpickup circuit also controlled by said first trafiic responsive devicein the energized condition, an energizing circuit for said first timeelement device controlled by means including said control device in" itsnormal position and a back contact of -said'first approach lockingrelay, another pickup circuit for said first approach locking relaycontrolled by means including a contact controlled by said first timeelement device to become closed when said first time element device hasbeen energized for a given measured period of time, a first pickupcircuit and a stick circuit for said'second approach locking relaycontrolled by means including a front contact of said first approachlocking relay and said first pickup circuit for said'second approachlocking relay also controlled by said second traffic responsive devicein the energized condition, an energizingcircuit for said second timeelement device controlled by means including a front contact ofsaid'first approach locking relay and a back contact of saidsecondapproach locking relay, another pickup circuit for said second approachlocking relay controlled by means'including a contact closed in responseto energization of said second time element device'a" second measuredperiod of time, and means including front contacts of said first andsecond approach locking relays for controlling said trafiic governingdevice;

11. In combination, a railway track, a signal for governing trafiicmovement in a given direction on said track, a first and a second timeelement device, control means including means responsive to a trainapproaching said signal in said given direction within a given distancein the rear of said signal for energizing said first time elementdevice, a directional stick relay, a pickup circuit for energizing saiddirectional stick relay in response to a train moving oppositely to saidgiven direction from a first portion of said track in advance of saidsignal to a second portion of said track in the rear of said signal, astick circuit for then retaining said stick relay energized while saidtrain occupies said second portion of said track, an approach lockingrelay, manual control means manually operable from a normal condition toa control condition for controlling said signal to display a proceedindication, a stick circuit and a first pickup circuit for said approachlocking relay controlled by means including said manual control means inits normal condition and said first pickup circuit also includingtraflic responsive means which is normally closed but which becomesopened when a train occupies said track within said given distance inthe rear of said signal, energizing circuit means for said second timeelement device including means controlled by said manual control meansin its normal condition and a back contact of said approach lockingrelay and also including a front contact of said directional stick relayconnected in multiple with a contact which is controlled by said firsttime element device to become closed when said first time element devicehas been energized for a measured period of time, another pickup circuitfor said approach locking relay controlled by means including saidsecond time element device in the energized condition, and trafiicgoverning means controlled by means including a front contact of saidapproach locking relay.

12. In combination, a railway track, a signal for governing tralficmovement in a given direction on said track, a first and a second timeelement device, control means including means responsive to a trainapproaching said signal in said given direction within a given distancein the rear of said signal for energizing said first time elementdevice, a directional stick relay, a pickup circuit for energizing saiddirectional stick relay in response to a train moving oppositely to saidgiven direction from a first portion of said track in advance of saidsignal to a second portion of said track in the rear of said signal, astick circuit for then retaining said stick relay energized while saidtrain occupies said second portion of said track, an approach lockingrelay, manual control means manually operable from a normal condition toa control condition for controlling said signal to display a proceedindication, a stick circuit and a firstpickup circuit for said approachlocking relay controlled by means including said manual control means inits normal condition and said first pickup circuit also includingtraffic responsive means which is normally closed but which becomesopened when a train occupies said track within said given distance inthe rear of said signal, energizing circuit means for said second timeelement device including means controlled by said manual control meansin its normal condition and a back contact of said approach lockingrelay and also including a front contact of said directional stick relayconnected in multiple with a contact which is controlled by said firsttime element device to become closed when said first time element devicehas been energized for a measured period of time, another pickup circuitfor said approach locking relay controlled by means including saidsecond time element device in the energized condition, other controlmeans including means controlled by said manual control means in itsnormal condition and a back contact of said approach locking relay andalso a contact which becomes closed in response to a train moving fromsaid first portion to said second portion of said track for energizingsaid first time element device, and traffic governing means controlledby means including a front contact of said approach locking relay.

13. In combination, a railway track, a signal for governing trafiicmovements in a given direction on said track, an approach portion ofsaid track in the rear of said signal, a polarized approach relaynormally energized by current of normal polarity if said approachportion of said track is unoccupied but becoming deenergized if a trainmoving oppositely to said given direction enters said approach portionof said track, a directional stick relay, pickup circuit means forenergizing said directional stick relay in response to a train moving inonly said given direction onto said approach portion of said track,stick circuit means for then retaining said directional stick relayenergized while said approach portion is occupied, means controlled bysaid directional stick relay in the energized condition for energizingsaid polarized approach relay by current of reverse polarity, a slowrelease relay controlled by a front neutral contact of said polarizedapproach relay, time element means, an energizing circuit for said timeelement means controlled by a reverse polar contact of said polarizedapproach relay and by a front contact of said slow release relay, signalcontrol means operable from a normal condition to a control conditionfor controlling said signal to display a proceed indication, an approachlocking relay, a stick circuit and a first and a second pickup circuitfor said approach locking relay controlled by means including saidsignal control means in the normal condition, said first pickup circuitalso controlled by means including a normal polar contact of saidapproach relay and said second pickup circuit also controlled by saidtime element means in an operated condition, a second energizing circuitfor said time element means controlled by means including said signalcontrol means in its normal condition and by back contacts of saidapproach locking relay and said slow release relay, and traflicgoverning means controlled by means including a front contact of saidapproach locking relay.

References Cited in the file of this patent UNITED STATES PATENTS2,013,986 Langdon Sept. 10, 1935 2,334,506 Pflasterer Nov. 16, 19432,369,113 Allen Feb. 13, 1945 2,385,179 Allen Sept. 18, 1945

